DropSource.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / WinForms / Managed / System / WinForms / DropSource.cs / 1305376 / DropSource.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

 
namespace System.Windows.Forms 
{
 	using System; 

	/// 
        internal class DropSource : UnsafeNativeMethods.IOleDropSource {
 
            private const int DragDropSDrop    = 0x00040100;
            private const int DragDropSCancel  = 0x00040101; 
            private const int DragDropSUseDefaultCursors = 0x00040102; 

            private ISupportOleDropSource peer; 

            public DropSource(ISupportOleDropSource peer ) {
                if (peer == null)
                    throw new ArgumentNullException("peer"); 
                this.peer = peer;
            } 
 
            public int OleQueryContinueDrag(int fEscapePressed, int grfKeyState) {
                QueryContinueDragEventArgs qcdevent = null; 
                bool escapePressed = (fEscapePressed != 0);
                DragAction action = DragAction.Continue;
                if (escapePressed) {
                    action = DragAction.Cancel; 
                }
                else if ((grfKeyState & NativeMethods.MK_LBUTTON) == 0 
                         && (grfKeyState & NativeMethods.MK_RBUTTON) == 0 
                         && (grfKeyState & NativeMethods.MK_MBUTTON) == 0) {
                    action = DragAction.Drop; 
                }

                qcdevent = new QueryContinueDragEventArgs(grfKeyState,escapePressed, action);
                peer.OnQueryContinueDrag(qcdevent); 

                int hr = 0; 
 
                switch (qcdevent.Action) {
                    case DragAction.Drop: 
                        hr = DragDropSDrop;
                        break;
                    case DragAction.Cancel:
                        hr = DragDropSCancel; 
                        break;
                } 
 
                return hr;
            } 

            public int OleGiveFeedback(int dwEffect) {
                GiveFeedbackEventArgs gfbevent = new GiveFeedbackEventArgs((DragDropEffects) dwEffect, true);
                peer.OnGiveFeedback(gfbevent); 
                if (gfbevent.UseDefaultCursors) {
                    return DragDropSUseDefaultCursors; 
                } 
                return 0;
            } 
        }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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